In the course of the surface preparation technique of cochlear histology, it is necessary to remove the bone from around the membranous portions of the cochlea. In ears in which the cochlea is encased in thick bone, the bone must first be thinned by grinding before it can be removed. This grinding is often done in a fluid bath, i.e. a Petri dish filled with ethanol or distilled water. This fluid quickly becomes clouded with bone dust which obscures the view of the specimen, and the specimen must then be transferred to a fresh Petri dish with clean fluid and the process repeated.